The mechanized harvesting of blueberries is now well established. Machines are constructed to straddle the bushes, and subject them to the action of beaters that knock the berries loose to fall on a collection system that ultimately conveys the berries to a receptacle. The principle is simple, but there are practical difficulties. Mature blueberry bushes in Michigan tend to be about six to eight feet high, and the same in width. In the southern states, or where other varieties are grown, ten foot bushes are common. A self-powered and propelled machine capable of straddling and working over bushes of this size becomes an imposing and expensive structure.
These bushes may be expected to last from twenty years to indefinitely, but require about seven years to come into significant production. They are not effectively handled by the conventional machines until the bushes have had about 14 years of growth. Smaller bushes have been picked manually where market conditions and labor costs make this cost effective. The rest of the crop is just abandoned, along with a substantial loss that machines miss on the smaller bushes. Usually, it is not practical to pick bushes manually until they are over seven years old.
Field laborers are paid by the picked pound, but the lower limit of the earnings is set by minimum wage requirements. If work is scarce, workers may work for the lower returns. There is considerable reluctance to accept the continued bending-over that is associated with picking small bushes.
This invention is intended to provide a machine that can effectively pick bushes with about three years of growth, and continue to work on these bushes for the next 10 years. The larger conventional machines then take over. The first couple of years after the three-year beginning point will represent cost recovery; but after that, a profitable operation can be expected. Market conditions will determine the breakpoints, but the result of mechanizing the operations on the smaller bushes is a vast saving over manual harvesting. The need for large groups of migrant field hands, with the attendant problems, is reduced or eliminated entirely.
This machine was initially developed for harvesting blueberries, but has since been found useful (with minor modification) on vine crops such as grapes and tomatoes, and for blackberries and raspberries.